Báo cáo toán học: "On Planar Mixed Hypergraphs" pps

... A planar mixed hypergraph may not have a strong embedding. We prove an easy lemma on the number of faces of size two in an embedding of a planar mixed hypergraph: Lemma 1 Let H be any planar mixed ... of planar mixed hypergraphs — similar properties of planar mixed hypergraphs were already used in [10, 15]. We address properties of feasible sets and existence of strict col...

Ngày tải lên: 07/08/2014, 06:22

... graph as a planar embedding of a maximal hypergraph such that the faces of the graph correspond to the edges of the hypergraph. 3 Colouring planar mixed hypergraphs Let H =(V,C, D) be a mixed hypergraph. ... colouring properties of general planar mixed hypergraphs was first raised in [13] (problem 8, p.43). It is evident that every planar D-hypergraph is colourable, just as every...

Ngày tải lên: 07/08/2014, 06:22

Ngày tải lên: 07/08/2014, 08:20

... and of mixed hypergraphs with maximum degree two [11, 12] are gap-free. Feasible sets of mixed hypergraphs with maximum degree three need not to be gap-free. The feasible sets of planar mixed ... Kratochv´ıl, H J. Voss: Mixed Hypegraphs with Bounded Degree: Edge- Coloring of Mixed Multigraphs, Theoretical Comp. Science 295 (2003), 263–278. [13] D. Kr´al’, J. Kratochv´ıl, H J. Voss...

Ngày tải lên: 07/08/2014, 08:20

Ngày tải lên: 07/08/2014, 07:21

Ngày tải lên: 07/08/2014, 07:21

Ngày tải lên: 07/08/2014, 07:21

... Fak. Ser. Mat., 9 (1979), 185-190. the electronic journal of combinatorics 14 (2007), #R51 15 On Mixed Codes with Covering Radius 1 and Minimum Distance 2 Wolfgang Haas Albert-Ludwigs-Universit¨at Mathematisches ... and K q (n + 1, 1, 2) ≤ q · K q (n, 1, 2), see [4, 3, 8, 6]. A natural generalization is to consider mixed codes with covering radius 1 and mini- mum distance 2. In the whole...

Ngày tải lên: 07/08/2014, 15:22

... 05A16, 05C20, 05C30 1 Introduction A planar map is a planar graph together with a crossing-free drawing in the plane. Many different structures on connected planar maps have attracted the attention ... we study bipolar orientations on the square grid, stacked triangulations, outerplanar maps and planar maps. The upper bound for planar maps relies on a new encoding of bipolar orientat...

Ngày tải lên: 07/08/2014, 21:20

Ngày tải lên: 08/08/2014, 12:22